1. Field of the Invention
The invention relates to a reactor unit whose reactor bodies can be cooled efficiently.
2. Description of the Related Art
Heretofore, there has been known a reactor unit whose smoothing reactors, which are used for an electric power converter, for example, a converter, an inverter or the like, can be cooled efficiently. For instance, such a reactor unit is disclosed in Paragraph 0007 and FIGS. 1 and 2 of Japanese Patent Application Laid-Open No. 5-109542.
In the reactor unit disclosed in Japanese Patent Application Laid-Open No. 5-109542, reactor bodies, each of which is constructed by winding a pair of coils around an iron core, are accommodated in a metal box-type case exhibiting a high thermal conductivity, and a space formed in the case is filled with a resin insulant exhibiting a high thermal conductivity.
A curable resin such as epoxy resin or the like is used as the resin insulant that is high in thermal conductivity. Shrinkage or the like of the resin occurring during curing thereof causes problems. That is, the resin insulant in the metal box-type case is detached from an inner face thereof, and the metal box-type case undergoes deformation such as distortion or the like.
Hence, in order to prevent such detachment or deformation, there has been known another technology. According to this technology, a basket body made of a metal and having one open face, reactor bodies accommodated in the basket body, a lid body made of a metal and closing an open end of the basket body, and a curable mold resin filling the interior of the basket body are provided. Eight spaces to be filled with the mold resin are formed between the reactor bodies and the lid body. These spaces are separated from one another by a pair of cruciform spacers and a plate-type spacer located between the cruciform spacers. The spaces thus defined serve to reduce shrinkage ratio of the mold resin. For instance, such a technology is disclosed in Paragraph 0007 and FIGS. 1 and 2 of Japanese Utility Model Application Laid-Open No. 4-133486.
A reactor unit constructed as described above and disclosed in Japanese Utility Model Application Laid-Open No. 4-133486 serves only to reduce shrinkage ratio of the mold resin and cannot suppress shrinkage thereof sufficiently. In particular, the lid body is designed simply as a plate and thus cannot be prevented from being deformed.